Here's a list of videos on how to properly use a quick release. (OP's bike does have the traditional skewer through axle type of QR)
https://www.bing.com/search?q=how+to...EESS&PC=SCOOBE I just included a bunch of them so you can watch several if it's not clear at first. if in doubt, take it back to REI and have them show you how.